Cybersecurity Series B Funding 2026: Round Sizes

Cybersecurity Series B rounds in 2026 range from $37 million to $125 million, and the disclosed valuations behind them — $700 million to $1 billion — show investors paying more for less deal volume across the sector.

That's the picture from ten real, disclosed 2026 cybersecurity financings, cross-checked against PitchBook's Q2 2026 Cybersecurity Report and Crunchbase News' H1 2026 funding tracker. Neither source invents an "average Series B" — this post builds one from the actual companies that raised at that stage this year, then compares it against the sector's broader stage-by-stage benchmarks.

No two data providers slice "cybersecurity" the same way, and no single tracker captures every private round, so this benchmark leans on named, dated, sourced deals rather than a blended industry average that can't be traced back to a specific company. Where a figure comes from an aggregate report instead of a single disclosed round, that distinction is called out explicitly below.

What is a typical cybersecurity Series B funding round in 2026?

A typical cybersecurity Series B funding round in 2026 lands between $100 million and $125 million, based on six disclosed deals from January through September: HiddenLayer ($100M), Exaforce ($125M), Vega Security ($120M), Noma Security ($100M), Twenty ($100M), and Dropzone AI ($37M), which is the outlier on the low end. Post-money valuations on the deals that disclosed one ran from roughly $700 million to $1 billion.

Every one of those six is an AI-security company by product category — endpoint, SOC automation, agent security, or model security — which is itself a data point: the companies clearing $100M+ Series B rounds in 2026 are almost all selling AI-native tooling, not traditional network or identity security, where later-stage rounds and acquisitions (not fresh Series B checks) have dominated the headlines instead.

What counts as "Series B" also isn't always clean-cut. Exaforce, HiddenLayer, Vega Security, Noma Security, Twenty, and Dropzone AI all used that exact label in their own announcements or in the reporting on their rounds. Alice's $140 million round, by contrast, is described by its lead investor Apax Digital — a private-equity growth firm, not a traditional venture fund — as a growth financing rather than a numbered Series letter, which is part of why this post treats it separately from the core Series B set instead of folding every large check into one bucket.

The 2026 cybersecurity Series B deals, ranked

Exaforce's $125 million round, announced May 12, 2026 with participation from HarbourVest, Peak XV, Mayfield, Khosla Ventures, and Seligman Ventures, is the largest disclosed Series B of the year — coming just one year after a $75 million Series A and pushing total funding to $200 million at a $725 million valuation. Vega Security's $120 million, led by Accel with Cyberstarts, Redpoint, and CRV, closed February 10, 2026 and nearly doubled the company's valuation to roughly $700 million on $185 million raised to date. HiddenLayer's $100 million, led by Delta-v Capital with Ten Eleven Ventures, Morgan Stanley, M12, and Booz Allen Ventures, closed September 2, 2026 — the most recent round in this set — without a disclosed valuation.

Twenty's $100 million round, covered in full in our Series B breakdown, closed June 17, 2026 at a $1 billion valuation led by Accel — the highest disclosed valuation of any 2026 cybersecurity Series B. Going back to 2025 for comparison, Noma Security's $100 million round (led by Evolution Equity Partners, closed July 31, 2025) and Dropzone AI's $37 million round (led by Theory Ventures, closed July 28, 2025) bracket this year's range from below, suggesting round sizes held flat to slightly up year over year for companies that reached this stage.

How Series B compares to Series A, C, D, and later rounds

Series B sits in the middle of a curve that steepens fast. Glow emerged from stealth at a $1.2 billion valuation on a $180 million Series A in July 2026 — a larger round and valuation than most of this year's Series B deals — while XBow's $120 million Series C crossed a $1 billion valuation in March 2026. By the time a cybersecurity company reaches Series D or later, round sizes and valuations jump again: Chainguard's $356 million Series D valued it at $3.5 billion in April 2025, and Cyera's $600 million Series G hit $12 billion in June 2026.

Sources: TechCrunch, SecurityWeek, GeekWire, PRNewswire, and pulse2.com, 2025-2026. Chainguard's earlier valuation history is detailed in our own Chainguard valuation breakdown.

Why valuations are climbing even as deal count falls

PitchBook's Q2 2026 report found the sector's median pre-money valuation more than doubled from year-end 2025 to $72.2 million, and Series C pre-money valuations specifically surged 166.4% to $845.9 million — even as total H1 2026 deal count fell 23.8% year over year to 380. Security operations led every segment on transaction count, with 47 deals totaling $1 billion in Q2 alone as investors backed agentic threat detection. Nine-figure rounds took 81% of every dollar invested in cybersecurity in Q2 2026, more than double the share they held at the start of 2018.

Exit activity backs up the pricing: PitchBook counted $9.1 billion in cybersecurity exits across 31 transactions in Q2 2026, the strongest quarter for exit value since Q3 2021, driven in large part by ServiceNow's $7.8 billion acquisition of Armis. When acquirers are paying that much for proven companies, Series B investors have a real comparable to point to when they write a $100 million-plus check into a three-year-old startup — the exit math, not just the product roadmap, is underwriting these valuations.

The other force at work is category concentration. Nearly every disclosed 2026 Series B in this dataset — HiddenLayer, Exaforce, Vega Security, Noma Security, and Twenty — sells a product built specifically around AI: securing AI models and agents, or using AI to automate security operations. Traditional categories like network firewalls or identity management raised plenty of capital too, but mostly at later stages or through acquisitions rather than fresh, headline-making Series B rounds, which is one reason this benchmark skews so heavily toward AI-native companies rather than the sector as a whole.

Cyera's valuation climb shows how fast the ladder moves after Series B

No 2026 cybersecurity company illustrates the post-Series-B trajectory better than Cyera. Its last four rounds alone — Series D through Series G — took its valuation from $3 billion to $12 billion in nineteen months, a run that would look implausible in almost any other software category outside AI.

Growth-stage rounds show where Series B winners end up

Two more 2026 deals sit just past Series B and show how far the valuation ladder can climb once a cybersecurity company proves out its go-to-market. Alice — the AI security company formerly known as ActiveFence, covered in our full valuation breakdown — raised $140 million in a growth round led by Apax Digital that closed August 25, 2026, pushing its valuation to a reported $800 million to $1 billion range on AI-security revenue approaching $100 million in ARR after growing more than 500% in two years.

Horizon3.ai tells a similar story from the offensive-security side: its August 2026 Series E valued the seven-year-old startup at $2 billion, up 3x from $650 million just a year earlier, on ARR nearing $100 million and 120% growth. Neither company's most recent round is technically a Series B, but both crossed that stage on the way to these numbers — which is the real argument for why 2026 Series B investors are willing to write $100 million-plus checks at $700 million-to-$1 billion valuations: the next two or three rounds, if the company executes, can be worth multiples more.

Line up the four companies with the longest funding history in this dataset — Twenty, Chainguard, Horizon3.ai, and Cyera — and the pattern is the same in each case: a Series B or Series C that looked large at the time turned out to be a fraction of what the company was worth twelve to eighteen months later. That doesn't mean every 2026 Series B will compound the same way, but it does explain why investors are paying up for the stage now rather than waiting for a cheaper entry point at Series C or D.

What the headline misses

Every "typical Series B" figure in this post is built from the handful of rounds that got disclosed publicly, not a complete census — HiddenLayer, Dropzone AI, and Noma Security didn't disclose valuations, and plenty of cybersecurity Series B rounds never get announced at all, especially smaller ones outside the AI-security category that's driving most of this year's headlines. PitchBook's $72.2 million median pre-money figure also blends every stage from seed through growth into one number, so it understates what a company actually clearing Series B is worth relative to the sector as a whole. And Crunchbase's Q2 2026 tracker showed cybersecurity funding down roughly 30% quarter over quarter to $4.4 billion even as PitchBook's H1 total held flat — the two trackers use different sector definitions and reporting windows, so treat any single quarter's swing as noisy rather than a clean trend line.

What this means for cybersecurity founders raising a Series B

For a founder modeling a 2026 raise, $100 million is now a realistic Series B target if the product has clear AI-security positioning and early enterprise logos — five of six disclosed 2026 deals hit that mark or higher. This likely means investors are underwriting Series B checks against the same exit comparables (Armis at $7.8 billion, Wiz at $32 billion) rather than against typical SaaS Series B benchmarks, which is good news for AI-native security startups and a harder bar for traditional network or identity-security companies without that framing. The flip side is the 23.8% drop in overall deal count: capital concentrating into fewer, larger rounds means a startup that doesn't clear the bar for a nine-figure check may struggle to raise a Series B at all in 2026, rather than settling for a smaller one the way it might have in a less concentrated market.

Dropzone AI's $37 million round is the useful counterexample: it shows a real Series B still gets done well below the $100 million cluster when a company has strong revenue growth — Dropzone disclosed 11x annual recurring revenue growth in the same year it raised — even with a smaller check size than its peers. A founder targeting a smaller, more disciplined Series B shouldn't read the $100 million-plus headlines as a hard floor; the underlying metric investors are pricing is revenue growth and enterprise traction, and round size follows from there rather than the other way around.